Circuit controller



Feb. 15, 1944. w BUTLER r 2,341,901

0 IRCUIT CONTROLLER I. Original Filed June 18, 1941 plgl Fl.2.sg s:l87071 75 76 17 67 45 Gla, i l I 65 ,f/ IO Imventors:

William Lawrence Butler;

George M. Haueler,

Th n" ALtormey.

PatentedFeb. 15, 1944 CIRCUIT CONTROLLER William Lawrence Butler,Schenectady, and

George M. Hausler, Ballston Lake, N. Y., assignors to General ElectricCompany, a corporation of New York Original application June 18, 1941,Serial No.

398,608. Divided and this application November 28, 1942, Serial No.467,206

8 Claims.

Our invention relates to circuit controllers, and particularly to meansfor minimizing or preventing vibration of circuit controller contacts.This application is a division of our copending application Serial No.398,608, filed June 13, 1941, now Patent 2,310,730.

It is one object of our invention, generally stated, to provide anelectric circuit controller which shall have improved eiliciency ofoperation and which shall be inexpensive and easy to manufacture inlarge quantities.

More specifically, it is an object of our invention to provide means forminimizing vibration and chattering of cantilever spring electriccontact elements.

It is a still further object of our invention to provide new and noveladjustment means for cantilever spring contact elements.

By way of illustration we have chosen to show our invention applied to amultipoint electromagnetic motor starter of the type disclosed in PatentNo. 2,223,278 issued on November 26, 1940, to Fred H. Winter. The motorstarter disclosed in the Winter patent comprises a contactor having aplurality of armatures which are arranged for sequential dropout tocontrol a plurality of normally closed resistance shunting switches. Thearmatures cooperate with magnetically independent cores which arearranged for simultaneous energization by a single actuating coil. Thestarter also includes certain interlock switches which have a particularutility in connection with systems similar to those disclosed in thepatent. According to the invention the resistance shunting switches arecarried by light cantilever leaf springs which are adjustably attachedto a contact carrying head portion of the controller mounted adjacentthe electromagnet armatures. A second and relatively heavy cantileverspring is mounted in conjunction with each light contact carrying springto overlie the light spring in parallel engaging relation therewith forthe purpose of restraining vibration of the contacts. I'he heaviercantilever spring is fixedly connected to the fixed end of the lightspring and is connected at its free end through a lost motion connectionto the free end of the light cantilever spring. Both springs are biasedin a circuit closing direction, so that when in the closed position theheavy spring lies against the light spring to prevent chattering of thecontacts.

Our invention itself will be more fully understood and its objects andadvantages adequately appreciated by referring now to the followingdetailed description taken in conjunction with the accompanying drawing,in which Fig. l is a side elevation, partly in section, of our circuitcontroller showing the armatures in their normal deenergized positions;Fig. 2 is an end view of the controller with the parts in the samepositions as in Fig. 1; Fig. 3 is a plan view of the controller showingparticularly the interlock switch assembly on the controller head; Fig.4 is a fragmentary view similar to Fig. 1 showing the movable parts ofthe controller in their actuated positions; and Fig. 5 is an enlargedperspective view of an armature hinge construction, preferably formingpart of our circuit controller.

Referring now to the drawing, our circuit controller in one formcomprises a frame including a base plate l0 upon which are mounted threeU-shaped magnetic cores ll, [2, and I3 and four perpendicular mountingstuds I4, l5, l6, and I1 and a contact head assembly generallydesignated by the numeral l8 supported upon the studs l4, l5, l6, andIT. The three U-shaped cores H, l2, and 13 are disposed in alignmentwith their side legs extending perpendicularly from the base illtofacilitate the mounting of a common actuating coil upon the forwardlegs of all the cores.

As best shown at Figs. 1 and 4, each of the U-shaped cores is providedwith a magnetic armature 20 arranged across the end faces of the corelegs in transverse abutting relation thereby to bridge the gap betweenthe legs at their outer ends. Since the three electromagnets are ofsimilar construction, only one need be described by way of example. Thearmature 20 of Fig. l is pivotally mounted adjacent the end face of therear leg of the core H and biased to a normal position in spacedrelation to the end face of the forward core leg by means of a resilienthinge member Zi. Referring now particularly to Fig. 5, it will beobserved that the resilient hinge member 2i is channel-shaped incrosssection and is stamped to provide a pair of connected bowed springfingers 25 and 26 extending upwardly from the lower end of the hinge.Adjacent the armature 20 the hinge member 2| is bent inwardly to providea shoulface the rear leg of the core member is provided with a generallyT-shaped projection 29 forming upon its side nearest the base It atransverse notch 30 adapted to receive the free ends of the springfingers and Ed. The notch is preferably slightly offset laterally fromthe leg of the core ll as is best shown at Fig. 5. The other side of theT-shaped projection 29 forms with the rear leg of the core H atransverse groove 3! within which the shoulder 2'! is seated in theassembled position. As may now be seen by examination'of Figs. 1 and i,the rear face of the armature 2d slightly overhangs the rear leg of thecore I! due to the presence of the inwardly turned shoulder 21. Becauseof this slight overhang the longitudinally extending hinge 2| lies inparallel spaced relation to the rear leg of the core when the armature2B is in its attracted position. The dropout movement of the armature 20is limited by engagement of the lower end of the hinge 2| with the coreleg.

In operation the armature 2i] pivots about the knife edge formed by theinwardly projecting shoulder 21 in moving from its deenergizedpositionin Fig. 1 to its attracted position in Fig. 4. In pivoting aboutthe knife edge 21 to the position of Fig. 4 the lower end of the hinge2! moves through an are which brings it closer to the notch 30 againstthe bias of the spring fingers 25 and 26. The tendency of the springfingers 25 and 26 to assume a straight position normally forces thelower end of the hinge member 2 Ito the position shown in Fig. 1 andthus biases the armature 2b to its deenergized position spaced from thefront leg of the core H.

The movable ends of the armatures 20 are arranged to engage the endfaces of the front legs of the cores Ii, 12, and i3 in their actuatedpositions. Since it is essential to the operation of this device thatthe dropout voltage of each of the armatures be accuratelypredetermined, it is necessary to provide means for preventing thearmatures from sticking to their associated cores due to the residualmagnetism of the cores. For this purpose we have shown shims 32 ofsuitable nonmagnetic material fastened to the lower sides of thearmatures 20 in the region of their engagement with the cores ll, 12,and is.

To provide for operating the various motor controlling and interlockcontacts associated with our circuit controller, the movable end of thearmature 20 has attached thereto a block of insulating material 33formed to provide a contact operating pin 34 and a damping buffer 35.

The contact carrying controller head it comprises a fiat base til formedof a molded insulating compound and mounted upon the outer ends of thestuds It, l5, l6, and ll. The base W has mounted upon the inner sidethereof a plurality of movable motor controlling contacts (ii andcarries upon its outer surface a number of interlock contacts whichpreferably are connected in circuit as shown in the above-mentionedWinter Patent No. 2223,278 and will be described in greater detailhereinafter. As best shown at Figs. 1 and 4, each of the movable motorcontrolling contacts M is mounted upon the free end of a relativelylight cantilever spring 12 which is biased toward the base 66 to'holdthe contacts at in engagement with cooperating fixed contact strips 43mounted upon the inner side of the insulating base It. Each of the fixedcontact strips 43 is formed to provide atthe opposite end thereof aterminal conductor extending beyond the in= sulating base 48.

Each cantilever spring 52. is connected in spaced relation to the innerside of the base it by means of a bolt 35 extending through the base tiland threaded into a plate d6 below the spring. The contact carryingcantilever springs are thin and of relatively small mass so that theirinertia and hence their tendency to rebound after engaging thestationary contacts 63 are rrfinimized. To further assist in preventingrebound of the movable contacts at and to increase the contact pressurewhen the contacts are in their normal closed positions, a secondrelatively heavy cantilever spring ll is also mounted upon each bolt 45adjacent and parallel to the spring 62. As shown in Winter Patent No.2,223,278, all the movable contacts of this type of circuit controllerare connected together to a common external terminal. In our improvedcontroller this connection is effected and the cantilever springs 62 andt? are spaced from the base h by a T-shaped contact plate it whichextends across the rear side of the'base ii] and is pierced by each ofthe spring securing bolts 65 (Fig. 3). The contact plate it? alsoextends beyond the rear side of the base to provide a common externalterminal connector. The heavy springs are biased toward the base it andinto engagement with the relatively light springs d2 along substantiallytheir entire length.

To provide" for operative connection of the contacts ll to the movableends of the armatures 20, the relatively heavy springs ll are slit andbent toward the armatures to form slotted hang ers 49 to receive thepins 35 and to leave central forwardly; extending pins 5b. The free endsof the light cantilever springs 32 are similarly slotted and bent towardthe armatures in parallel spaced relation to the hangers '39 to formhooks for/engaging the pins 553. Since the springs til are biased towardthe controller head it, the hangers d9 assist the spring hinges 2i inmoving the armatures to their deenergized positions.

In. order to insure a constant preadjusted minimum pressure at thecontacts li li-i the cantilever springs 32 and ii are provided withadjusting bolt 36 which passes through the insulating base 36 slightlyforward of the spacer and is threaded into the plate 36 to draw thecantilever springs 42 and i? toward the base 5-53. Each bolt Gilcomprises a lower externally thread ed shank portion extending from thebottom of the base id and a cylindrical head til posh tioned with acylindrical recess Eila in the base at and seated upon a shoulder formedat the bottom of the recess.

To provide for application of additional tension to the cantileversprings whereby the separate armature 26 may be independently adjustedto drop out in sequential timed relation as the energization of theactuating coil it decays, the cylindrical bolt heads Bl are threadedlongitudinally to receive second adjusting bolts heads of the bolts 82are seated upon removabie plates or washers 83 which rest upon shouldersformed by the top of the recesses Bid thereby to raise the entire boltsall from the shoulders at the bottom of the recesses.

Thus by removing the bolts and the plates 63 access may be obtained tothe lower bolts Each of the motor controlling contacts "15 m be adjustedfor a predetermined minimuih constant contact pressure by adjusting thelower bolt with the upper bolt 62 and the plate removed. When thedesired minimum contact pressure is obtained the permanence of theadjustments is ng contacts, may be replaced. The bolts may now beadjusted to determine and the bolts 62 the dropout voltages of thevarious armatures thereby provide a timing adjustment for the variousmotor controlling contacts to insure the desired sequential closure ofthe contacts as the energization of the coil is decays. If desired thepermanence of the timing adjustment when obtained may be insured bysoldering the bolts 62 to the nonro'tatably seated plates 63.

ltljounteci on the outer surface of the insulating base we have shown apair of interlock contacts lit and carried at opposite ends of a stripit? of electrically conducting material. The inter icclr contacts 65 and66 may of course be used in any desired circuit relation, but when ourcircuit controller is used in connection with the motor controllingsysternoi Winter Patent No. 2,223,278 we prefer to connect the contacts65 and St in l in a scanner similar to the interlock contacts F a and12% of the patent. The conducting l slotted and slidably mounted upon aof studs and till projecting from the base To bias the contact strip t?toward the base into contact engaging position, a pair of compressionsprings to, H is mounted between strip and a air of stops l2, '13 uponthe ds 32),, respectively, As shown in Figs. 1 l when the threearmatures Eli are in their zleenergizecl positions the contact strip511s forced contact disengaging position against the bias the "iii andll by a plurality of slidable Asher ro and ll. Each of the rods iii,

and, passes through the insulating base so engi 'ges one of therelatively stifi contact as The upper ends of the pusher rods ll, "l3,are provided with shoulders engag the under side of the contact strip 61and with extending tongue portions passing through the contact strip.

The extending tongue portions of pm. I

the pusher provided on all the rods only for the purpose uniformity,since in our preferred form of contactor only one of these extendingtongue portions is us it will be understood, however, that if desiredadditional interlock switches may 1 o added in connection with theextending "ues of the other pusher rods. By way of ex- 1318 we haveshown normally closed interlock react connected to one end of a pivotedlever the other end of which engages the extending of the pusher rodill. The lever ill is i to a projecting stud 82 mounted upon the and isbiased to contact opening position compression spring 33. However, withthe by ci cuit controller in its deenergized condition the s or rod israised and holds the interlock in its closed position. When ourcircontroller is used in the system disclosed in above roentioneciWinter patent we prefer to connect the interlock. contact so in a mannerv to the interlock contact 2c of the patent. peretion, when theactuating coil is is tl, three cores i i it, and it are simul L and thethree armatures A aneously drawn to their attracted ions. each armaturetil begins to move l its attract-es. position it draws with it the Lvelyheavy spring t'l. After a certain or lost motion the forwardly extenmhgon the free end of the spring el'engages the hook 55 on the relativelyspring (3;? draws the spring it away from the base open the motorcontrolling contacts the armatures to move toward their attrac o 'c 5sitions the consequent movement of the of the springs ll permits thesprings and. depress the contact strip Eli. and the pushe l5, l6, andii, thereby to close the con and 66. This movement of the pushe alsopermits the spring 83 to rotate the sci er in a clockwise direction, asviewed in Open the interlock contact as at Fig. As shown in the Winterpatent, release of manually operated start switch removes actuating coilfrom the line and permits charge of a timing condenser gradually to ciecthrough the coil ill. As the energization oi coil diminishes, thearmatures 2E5 are releases sequential time relation as determined thethickness of the shims i2 and by the adjusof the various bolts 62previously described. each armature 526i is released, it moves out thecore it along with both of the s rin s an it. When the contact ll thefitted co tact i3, the relatively light spring 33 l movement, and. theheavy spring ti ture 2i? continue to move to taite up the lost tion. Ashas been previously pointed out inertia of the relatively light spring#32 is so that no appreciable-rebound of the contact occ upon itsinitial engagement. As hec y s it continues to take up the lost motion.easement of the contacts and Gil, it l engages the light spring so alone35 ing length thereby gradually to incre lact pressure and to assist inpreventin of the contact i l. The armature 5 heavy cantilever spring sothat the of the armature, which is closely 49 spring 4t, tends toprevent oscillation or. t

heavy spring.

Regardless of which of the amatures first released, the release of thefirst irii raises the associated pusher rod to op 5 the contact 65 orthe contact and thus 20 the series interlock circuit through co tacts.If our circuit controller is user of the control systems disclosed in.the i patent, the last armature to be 50 associated with the core l3 andthe pus 'l'l. When this last is r pusher KOi'l engages the lev T it in acounterclockwise direction, Fig. 1, thereby to reclose interloc While wehave shown but one bodiment of our invention by way of manymodifications will occur to thoin the art, and we therefore wish to Z1.

derstood that we intend the ap or? to cover all such modifications as w;true spirit and scope of our invention What we claim as desire byLetters Patent oi the United l. A circuit controller comprisi h" c fixedcontact mounted s cantilever springs mounted upon saio parallel engagingrelation, one having a mass substantially les other of said springs ea amovable contact said light to maintain said movable so with said fixedcontact, springs overlying saic biased hold Gil gaging position, lostmotion connecting means between the free ends of said springs, and meansengaging the spring of greatest mass for moving both said springsagainst their bias to a contact disengaging position.

2. An electric circuit controller comprising a base, a fixed contactmounted upon said base, a relatively light cantilever spring connectedto said base and carrying at its free end a movable contact arranged forcooperation with said fixed contact, said spring biasing said movablecontact into contact engaging position, a second cantilever springfastened to said base and extending in substantially parallel engagingrelation to said first spring overlying said first spring and, saidsecond spring being biased to hold said first spring in a contactengaging position, a lost motion connection between the free ends ofsaid springs whereby said second spring loosely engages said firstspring to open said contacts, and actuating means connected to saidsecond spring to move both said springs to a contact disengagingposition.

3. An electric circuit controller comprising a base, relatively lightand relatively heavy cantilever springs mounted upon said base inparallel engaging relation, a movable contact mounted upon the free endof said light spring for cooperation with a fixed contact mounted uponsaid base, said light spring being biased to maintain said contacts inengaging position and said heavy spring overlying said light spring andbeing biased to a position of parallel engagement, the free end of saidlight spring being formed to provide a slotted projection extendingtoward and loosely engaging said heavy spring, said heavy spring beingformed to provide a second slotted projection, and an actuating pinarranged to engage said second slotted projectionfor moving both saidsprings against their bias to a contact disengaging position.

4. An electric circuit controller comprising a base of insulatingmaterial, a fixed contact mounted upon the one side of said base, arelatively light cantilever spring carrying at its free end a movablecontact for cooperation with said fixed contact and mounted upon saidone side of said base, the free end of said spring being slotted andbent away from said base to provide a hook, at relatively heavycantilever spring overlying said light cantilever spring in parallelengaging relation therewith, common means for connecting said springs tosaid base, both said springs being biased to maintain said contacts inengaging position, the free end of said heavy spring being slotted andbent away from said bases to provide a hanger and an extending pin, saidpin being arranged for loose engagement with said hook, and an actuatingpin of insulating material arranged to engage said hanger to move bothsaid springs against their bias, thereby to disengage said contacts.

5. An electric circuit controller comprising a base, cooperating switchcontacts, a cantilever spring for controlling one of said contacts,means for connecting one end of said spring in spaced relation to saidbase, an adjusting bolt engaging said spring intermediate its ends todraw the free end of said spring toward said base, said bolt having ahead seated upon a shoulder formed upon said base, and means foradjustably raising said head from said shoulder thereby further to drawsaid spring toward said base.

6. An electric circuit controller comprising a base, cooperating switchcontacts, a cantilever w spring for controlling one of said contacts,connecting means for fastening one end of said spring to said base,spacing means between said base and said one end of said spring, a firstadjusting bolt engaging said spring adjacent said spacing means to drawthe free end of said spring against said base with a predeterminedminimum pressure, said first bolt having an internally threadedcylindrical head seated upon a shoulder formed upon said base, and asecond adjusting bolt threaded into said head and seated upon a secondshoulder formed upon said base thereby adjustably to increase saidpressure.

7. An electric circuit controller comprising a base of molded insulatingmaterial, a fixed contact secured to said base, a cantilever springcarrying at its free end a movable contact, spacing means between thefixed end of said spring and said base, connecting means for fasteningsaid fixed end of said spring to said base, a first adiusting boltengaging said spring adjacent said spacing means to draw said contactsinto engagement with a predetermined minimum pressure, said first bolthaving a cylindrical head portion seated upon a shoulder formed at thebottom of a recess in said base, said cylindrical head being internallythreaded in alignment with said first bolt, a second adjusting boltthreadingly engaging said cylindrical head and having a head portionseated upon a second shoulder 49 formed upon said base therebyadjustably to increase said pressure, and actuating means connected tothe free endof said spring to open said contacts.

8. An electric circuit controller comprising a base, fixed and movableswitch contacts, a relatively light cantilever spring strip having afixed end mounted upon said base and carrying at its free end saidmovable contact, said spring being biased to a contact engagingposition, a second and relatively heavy cantilever spring strip mountedupon said base in the region of the fixed end of said light spring andoverlying said light spring in substantially parallel engaging relationtherewithon the side thereof remote from said 0 movable contact, saidheavy cantilever spring being biased in the same direction as said lightcantilever spring to hold said light spring in contact engaging positionthereby to prevent vibration of said movable contact, a lost motionconnection between the free ends of said springs, and actuating meansfor engaging said second spring to separate the free ends of saidsprings and to move said light spring to a contact disengaging position.

WHJHAM LAWRENCE BUTLER. I GEORGE M. HAUSLER.

